In this paper, effects of discharge parameters and modulation frequency on the signal of laser-induced fluorescence measurements of ion velocity distribution functions are investigated in the LIF Test Source. A maximum modulation frequency is found for each given set of parameters, beyond which the signal gradually declines. Meanwhile, this maximum modulation frequency occurred consistently at ~1/10 of the theoretical frequency limit and photon counts received by a photomultiplier tube, which indicates that as modulation frequency and the associated per-pulse-excitation-event count decrease, the transition from the macroscopic statistical signal to the microscopic probabilistic signal is a gradual process.

The aim of this study was to evaluate the association between prenatal and neonatal period exposures and the risk of childhood and adolescent nasopharyngeal carcinoma (NPC). From January 2009 to January 2016, a total of 46 patients with childhood and adolescent NPC (i.e., less than 18 years of age) who were treated at Sun Yat-sen University Cancer Center were screened as cases, and a total of 45 cancer-free patients who were treated at Sun Yat-sen University Zhongshan Ophthalmic Center were selected as controls. The association between maternal exposures during pregnancy and obstetric variables and the risk of childhood and adolescent NPC was evaluated using logistic regression analysis. Univariate analysis revealed that compared to children and adolescents without a family history of cancer, those with a family history of cancer had a significantly higher risk of childhood and adolescent NPC [odds ratios (OR) = 3.15, 95% confidence interval (CI) = 1.02–9.75, P = 0.046], and the maternal use of folic acid and/or multivitamins during pregnancy was associated with a reduced risk of childhood and adolescent NPC in the offspring (OR = 0.07, 95% CI = 0.02–0.25, P < 0.001). After multivariate analysis, only the maternal use of folic acid and/or multivitamins during pregnancy remained statistically significant. These findings suggest that maternal consumption of folic acid and/or multivitamins during pregnancy is associated with a decreased risk of childhood and adolescent NPC in the offspring.

The dependence of fishbone cycle on energetic particle intensity has been investigated in EAST low-magnetic-shear plasmas. It is observed that the fishbone mode growth rate, saturation amplitude as well as fishbone cycle frequency clearly increase with increasing neutral beam injection (NBI) power. Moreover, enhanced electron density and temperature perturbations as well as energetic particle loss were observed with greater injected NBI power. Simulation results using M3D-K code show that as the NBI power increases, the resonant frequency and the energy of the resonant particles become higher, and the saturation amplitude of the mode also changes, due to the non-perturbative energetic particle contribution. The relationship between the calculated energetic particle pressure ratio and fishbone cycle frequency is obtained as ${f_{\textrm{FC}}} = 2.2{(1000{\beta _{\textrm{ep,calc}}} - 0.1)^{5.9 \pm 0.5}}$. Results consistent with the experimental observations have been achieved based on a predator–prey model.

Several epidemiological studies have investigated that Na or K intakes might be associated with the metabolic syndrome (MetS). However, little evidence has evaluated the association between Na:K ratio and the MetS. In this study, we assessed the association between the dietary Na:K ratio and the MetS. The cross-sectional study was conducted among adults aged 18 years and older in Nanjing, using a multi-stage random sampling method, which resulted in a sample size of 1993 participants. Dietary Na and K intakes were assessed by 3 consecutive days of dietary recollection combined with condiments weighing method. Health-related data were obtained by standardised questionnaires, as well as physical examinations and laboratory assessments. The prevalence rate of the MetS was 36·5 % (728/1993). After adjusting for various lifestyle and dietary factors of the MetS, participants in the highest quartile of dietary Na:K ratio were at a higher risk of developing MetS (OR=1·602; 95 % CI 1·090, 2·353) compared with those in the lowest quartile. Each 1-sd increase in dietary Na:K ratio was associated with a higher risk of prevalent MetS (OR=1·166; 95 % CI: 1·018, 1·336). Among the components of the MetS, dietary Na:K ratio was positively associated with high blood pressure (quartile 3 v. quartile 1: OR=1·656; 95 % CI 1·228, 2·256) and hypertriacylglycerolaemia (quartile 4 v. quartile1: OR=1·305; 95 % CI 1·029, 1·655) in multivariate analysis. These results revealed that higher dietary Na:K ratio significantly increased the risk of the MetS in Chinese adults. Further studies are needed to verify this association.

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is being built by the Chinese and will be the largest single dish radio telescope in the world. FAST, with much increase in sensitivity, will give astronomers good opportunities to answer many fundamental questions in astronomy. Here we give a brief introduction of FAST and its enormous potential for studying Galactic and extragalactic masers.

Using vinyl-silsesquioxane modified with various amounts of tetraethoxysilane (TEOS) and titanium tetrabutoxide (TTB), two kinds of hybrid films, film-vinyl-silsesquioxane-TEOS (f-VSTE) and film-vinyl-silsesquioxane-TTB (f-VSTT), were prepared. The average transparency (AT) of the modified films was measured in the ranges of the visible light region (400–750 nm) and in the near-infrared region (750–2500 nm). The AT values in these ranges are about 88% to 94%, indicating that these high-AT films can provide crops with growth energy and improvement of the photosynthetic process efficiency. The TEOS additions result in a hybrid structure (containing SiO2); an adequate addition can cause an increase in the AT radiation from sunlight. On the other hand, the TTB additions result in a hybrid structure (containing TiO2) that causes a decrease in the AT. These results were validated using molecular dynamic simulation and were calculated (with Materials Stutio software) using the density of states and the energy-band structure of the vinyl-SSO, SiO2, and TiO2 building blocks.

Ball milling of ammonothermally synthesized GaN powders was performed in an ethanol solution for a variety of durations, resulting in average particle sizes of nanometer. The ball milled powders showed an obviously brightened color and improved dispersability, indicating reduced levels of aggregation. X-ray diffraction (XRD) peaks of the ball milled GaN powders were significantly broadened compared to those of the as-synthesized powders. The broadening of the XRD peaks was partially attributed to the reduction in the average particle size, which was confirmed through SEM analyses. On the other hand, rare earth doping of commercial GaN powders was also achieved through a ball mill assisted solid state reaction process. Rare earth salts were mixed with GaN powder by ball milling. The as-milled powders were heat treated under different conditions to facilitate the dopant diffusion. Luminescence properties of the rare earth doped GaN powders at near infrared range were investigated and the results were discussed.

Fundamental relations of surface instability for micro-scale multilayer thin film systems are derived based on the Hill and Hutchinson bifurcation theory and the volume average integral. In the present relations, a size effect is considered through generalizing the plastic hardening modulus to include the strain gradient hardening effects. By using the model, firstly, the parameter-controlled instability region is divided and analyzed, secondly, the surface instability of the multilayer thin films are analyzed. In the surface instability analysis, several kinds of failure band formations are obtained, such as the kink bands and the compressive buckling bands in vertical direction and in inclined direction. Moreover, the failure mechanism of the multilayer thin film system due to surface instability is used to interpret the microstructure features of the surface-nanocrystallization materials.

This paper reports optical studies on transparent electro-optic ceramics, 2%Er:PLZT and 0.5%Er-2.5%Yb:PLZT. Strong photoluminescence was observed in these polycrystalline ceramics in the 1550 nm region when pumped by diode lasers either at ∼970nm or ∼800nm. Efficient green upconversion luminescence was also observed. Co-doping Yb3+ did enhance the Er3+ emission in the 1550nm region when pumped with ∼970 nm diode laser. This work provides important information for developing microchip and high-power ceramic lasers using Er-doped PLZT ceramics.

Nanocomposite powders of Ni–Al2O3 (5 and 10 vol% Ni) were prepared from porous alumina preforms with high specific area (100 m2 g?1) impregnated with nickel nitrate. Samples were obtained by reduction under a controlled oxygen partial pressure either directly or through an intermediate step, giving nickel aluminum spinel. In both cases, homogeneous dispersions of nickel particles in the alumina matrix were achieved. The Ni particle size ranged from 10 to 100 nm, depending on the preparation conditions and temperature.